Well, have to admit that I'm biased, as I'm a Kiwi, but DH is a Brit, and after 3 years in NZ, and 2 back here, he is champing at the bit to get back there (as am I). Think my view of the UK is slightly jaded by the fact that we live in London, which is a pretty hard place to live. I'm pregnant (due in September), and really wouldn't want to bring up my kids in London. I think schooling is better in NZ (I have a number of NZ friends who have taught in London schools and say they wouldn't want their kids to go to school over here, but that's just their opinion, I really don't know too much about it) - the schools have big playgrounds and sports fields, unlike London schools. I also think that NZ kids seem to retain that air of innocence for a bit longer - London kids seem to be a bit 'harder' and grown up (but again, that could just be my personal bias).
As for the beach, you can do that as little or as often as you like - I have friends who go every night after work in the summer. We used to go in the weekends (I introduced DH to boogie boarding, and he was hooked), but that was generally because of where we lived. Would sometimes go in the evenings during the week for a walk though...
If you like outdoor activities and sports, the NZ lifestyle is going to really appeal. We played a lot of golf in NZ, but find access to courses and cost really prohibitive over here. The range of sports for kids is huge, and girls play too - this is my major bugbear over here, there doesn't seem to be much evidence of women participating in sports over here in the media, except at the highest level, which doesn't really provide great role models for young girls... But that's a whole other thread. Climbs back down off soapbox...
In terms of housing, you will get much more 'bang for your buck' in NZ - standard NZ houses are detached with a garden. The older ones tend to be wooden, but newer ones are brick and other materials (beware of brand new houses as there's been problems with leaky homes - always get a full survey done on anything under 10 years old to check for this!!!).
On the other hand, some people find that NZ is quite isolated and not quite as 'exciting' as living in the UK (guess this depends on what you consider to be exciting too...). It really depends what you're looking for I guess. Personally, I would give it a go and rent for a year or so to see how you like it before you sell up over here. It would be tough getting back into the housing market over here again if you were coming from NZ, so best to make sure you're sure before committing.
Hope that helps a bit??? Am trying to be balanced, as have been a bit negative about being here lately (battling with NHS maternity care, noisy upstairs neighbours stamping on our heads, rude people on the tube...), and don't want to paint a falsely rosie picture - there's downsides to everywhere (poor public transport in Auckland being one - much as I moan about the tube, I do think it's fantastic to live in a city the size of London and be able to live without a car quite comfortably!).
This has turned into an essay, and it's time to leave the office now - am more than happy to answer any more questions though!!